Conventionally, electric vehicles, including an electric automobile, and a hybrid vehicle, are designed to supply electric power stored in a secondary battery to an electric motor via an inverter or the like to thereby output a driving force for vehicle traveling. The secondary battery, typified by a lithium-ion battery, has its temperature increased by generation of Joule heat due to transfer of the electric power during traveling, charging, etc. If its temperature exceeds a predetermined temperature, the secondary battery might be degraded or broken. For this reason, a cooling device is required to maintain the battery at the predetermined temperature or less.
As the cooling device, a vapor compression refrigeration cycle that cools air for the interior to be blown into a vehicle interior is used, as disclosed in Patent Document 1. The refrigeration cycle device disclosed in Patent Document 1 includes a first evaporator that cools the air for the interior, and a second evaporator that cools the secondary battery. The first evaporator and the second evaporator are arranged in parallel to each other on the downstream side of a refrigerant flow through a radiator.